Compact multipath process heater



May 19, 1970 P. van WIESENTHAL 3,512,505

COMPACT MULTIPATH PROCESS HEATER Filed April 22, 1968 2 Sheets-Sheet 1 INVENTOR. PETER VON VWESENTHAL gm aid? A TTORNEYS United States Patent 3,512,506 COMPACT MULTIPATH PROCESS HEATER Peter von Wiesenthal, 17 E. 89th St., New York, N.Y. 10028 Filed Apr. 22, 1968, Ser. No. 722,830 Int. Cl. F22b 21/24 US. Cl. 122-356 1 Claim ABSTRACT OF THE DISCLOSURE This disclosure relates to direct-fired process heaters for use in petroleum refining, chemical manufacture and the like. A vertical cylindrical heater is presented which offers a. smaller furnace chamber than heretofore and which has a particularly simple outlet arrangement. A number of like paths are provided in the radiant coil with with each path having a like portion of vertical tubes mounted in a radial plane relative the furnace chamber and another like portion of its tubes mounted against the wall. A central outlet manifold positioned below the floor permits vertical growth relative the cylindrical walls. Burners are floor mounted and arranged between the radially oriented tubes.

BACKGROUND Fired heaters with several parallel flow paths encounter characteristic design difliculties. Fitting the several paths into such heaters can involved complex tube configurations which run up pressure losses and magnify sizes of furnace chambers. Frequently box designs must be used (instead of vertical cylindrical designs) consequently sacrificing structural economies.

SUMMARY The present design solves the foregoing problem by a novel and facile approach. In a vertical cylindrical process heater the radiant coil flow is divided into a plurality of like passes. Each pass has the same number of its tubes mounted in a radial plane inward of the cylindrical wall and another equal number of its tubes mounted against the wall. A central outlet manifold is positioned below the floor so that deflections between the tubes and the outlet manifold can accommodate vertical growth of the tubes as they change temperature.

It is the primary objective of this design to achieve desired multipath arrangement in a vertical-cylindrical furnace whereby the structural economies inherent in cylindrical construction can be achieved. Mounting tubes in radial planes as well as about the cylindrical wall vastly reduces the size of cylinder needed. Accordingly recourse to box-type furnaces is obviated. This design is also simple to construct and is otherwise extremely well suited to its intended purpose.

DESCRIPTION OF DRAWINGS The foregoing and other features will appear more fully from the accompanying drawings wherein:

FIG. I is a cross-sectional elevation view of a process heater which embodies the present invention and which is taken along the line I-I of FIG. II.

FIG. II is a cross-sectional view taken along line 11-11 of FIG. 1.

FIG. III is a half elevation relating this invention to the whole furnace.

3,512,506 Patented May 19, 1970 ice PREFERRED EMBODIMENT In the drawings setting 3 includes floor 4, roof arch 5 and vertical cylindrical wall 6 'which all enclose radiant furnace chamber 7 therewithin.

Furnace coil 8 comprises a plurality of passes 9, 11, 12, 13, 14, 15, 16 and 17 (as best seen in FIG. II) all organized in parallel flow relationship. Each pass 9, 11, 12, 13, 14, 15, 16 and 17 has the same number of its tubes 18, 19, 21, 22, 23, 24, 25 and 26 mounted vertically in radial planes inward of wall 6.

Hot gases are introduced into furnace chamber 7 by means of burners 36 which penetrate floor 4 and which communicate with a suitable source of fuel (not shown). Damper 37 provides additional air as needed for combustion of the fuel.

It is necessary to allow for vertical growth of furnace coil 8. Toward this objective central outlet manifold 38 is provided below floor 4 and axially relative cylindrical wall 6. Conduits 39 connect each of the passes 9, 11, 12, 13, 14, 15, 16 and 17 to outlet manifold 38 and these conduits 39 are arranged to deflect as cantilevers so that furnace coil 8 can grow vertically downward as such growth becomes necessary.

What is claimed is:

1. A process heater comprising in combination:

a setting which includes a floor as well as a roof arch and a cylindrical wall all enclosing a furnace chamber therewithin,

a damper mounted in the floor axially relative the cylindrical wall and organized to admit air to the radiant furnace chamber,

- a plurality of burners penetrating through the floor to introduce combustibles into the radiant furnace chamber to produce hot combustion gases therein,

the roof arch provided with a breeching and the setting further provided with a convection section above .the radiant furnace chamber arranged in flow communication with the breeching to receive the combustion gases therefrom,

flue means remote from the radiant furnace chamber and arranged in flow communication with the convection section to accommodate withdrawal of the combustion gases therefrom,

a convection coil comprising horizontal tubes mounted in the convection section and defining a box-like configuration,

the convection coil arranged for circulating a process stream through the convection tubes in an even number of convection flow paths each arranged with an equal number of tubes in parallel flow relationship relative the others,

a radiant coil comprising serpentined vertical tubes mounted in the radiant furnace chamber and organized in a like number of radiant flow paths to .the number of convection flow paths and with each radiant flow path in parallel flo-w relationship with the others,

each radiant flow path having a same number of its tubes mounted in a radial plane inward of the cylindrical wall and having another same number of its tubes mounted against the wall,

each vertical tube arranged outward of the horizontal projection of the convection coil,

a like number of crossover connections to the number of convection flow paths each mounted inward 3 4 of the setting and each connecting one of the conthe outlet manifold for delivery of the process stream vection flow paths to one of the radiant fiow paths thereto. for delivery of the process stream thereto, References Cited the burners arranged outward of the damper and between the radial planes defined by the vertical tubes, r UNITED STA?ES PATENTS an outlet manifold mounted below the floor and axially 0 2,372,991 4/1945 Walks et 122 356 l i the cylindrical wall, 2,523,971 9/1950 schutt 122-356 each of the radiant flow paths having terminations in 2,902,981 9/1959 Throckmorton et 12'2356 the vicinity of the cylindrical wall below the floor, radially oriented conduits connecting each of the termi- 10 CHARLES MYHRE Pnmary Exammer nations of the radiant flow paths in flow series with 

